The present invention generally relates to a resonance apparatus using a TM mode such as TM110 or the like.
An example of the prior art filter is provided wherein TM110 square-pillar dielectric resonators R1, R2, R3, R4 with their axial lines being within the same plane and being parallel to each other are fixedly disposed within a case operating as a cut-off waveguide as shown in FIG. 29. The respective both end faces of the resonators R1 through R4 are in close contact against the inner faces of the case 1. Both a dipole 2 for inputting use and a dipole 3 for outputting use are connected with a coaxial circuit.
Thus, the prior art filter of such construction as described hereinabove requires resonator spaces in accordance with the coupling factors of the respective stages. Accordingly, there are limitations in rendering the size smaller. Also, it is difficult to provide the characteristics of having attenuation poles.